Monday, 24 September 2012

Canon MF4100 series - scanner problem? Solved!

If your Canon multi-function scanner has suddenly stopped working and won't scan, and you're troubleshooting error messages like "Unable to open TWAIN source", "Cannot open TWAIN source", "Source initialization failed" on trying to scan, here's an easy solution to the problem that's worth trying.

I've not tried it on other i-Sensys MF4100 imageClass series devices, like MF4120 or MF4140, but it worked like a charm on my MF4150. In my case the scanner function on my Canon i-Sensys MF4150 LaserBase laser multifunction printer, copier, scanner and fax suddenly started playing up and it wouldn't scan anything, whatever application I tried to use, even though the printer and copier worked fine.

The MF Toolbox app appeared but, although previously it would automatically scan to PDF, nothing happened after that, no matter what buttons I clicked. Similarly with other scanning apps I tried, like Abbyy Finereader - I just got error messages.

I thought I'd have to reinstall the drivers, but on searching I found a great solution from Jeff Widmer which worked instantly - no rebooting, no unplugging etc! I'm posting it here, with slightly quicker steps.

So here's the step by step on how to get the scanner on your Canon MF4100 series multi-function device working again, for Windows 7 but you could try it for Vista and see (for techies: you just need to add a TWAIN folder's path to PATH):

  1. Open Windows Explorer or Computer, and navigate to
  2. Inside the twain_32 there should be another folder, open that folder too (in my case it's named "MF4100", yours may have a different name eg MF4120).
  3. Now hold down the Alt key and tap d. This changes and highlights what's in the Windows Explorer address bar.

  4. Just press Ctrl-c (hold down Ctrl, tap c) to copy that highlighted address line to your clipboard (or if you prefer the mouse, rightclick on that address and copy it in the usual way).
  5. Now go to your System Properties:
    1. The fastest way is to click the Windows Start icon bottom left, type in the search box (without the quotes) "sysdm.cpl" and hit Enter or click the Search icon.
    2. The slower way is to rightclick the Computer icon on your desktop, choose Properties, then on the left click Advanced System Settings.
  6. Make sure you're in the Advanced tab by clicking on "Advanced" at the top if necessary.
  7. At the bottom of the Advanced tab, click the "Environment Variables" button.

  8. In the box that pops up, in the top half (under "User variables"), check under the first column, Variable, and find the variable named "PATH".

  9. Either doubleclick on the PATH line, or single click on it then click Edit. You should get something like this:

  10. You'll see the "Variable value" box usually has a long line of text already in there, highlighted. Be careful NOT to delete anything in that line (click Cancel and try again, if you delete anything by accident). Instead, go to the very end of that line (you can click into the box, then use the arrow keys to go right to the end, or just hit the right arrow key once without clicking anything and you'll be there).
  11. Now at the end of that box, type in a semicolon ie ;
    Then paste in (Ctrl v) what you copied in step 4 above. No need to add any spaces anywhere, just the semicolon and the copied stuff. Here's what mine looked like after that:

  12. Then OK everything. In my case, my scanner immediately started working again, even without a reboot!

If that didn't work, you may need to try reinstalling the drivers. In the case of my MF4150 you have to install the drivers while the device is NOT plugged in to the computer via USB (or dire things may happen and the whole device may not work), but in other cases you can just plug it in, so you have been warned! For the MF4150 you'd unplug the USB cable from the printer/scanner, uninstall the device in Device Manager, reinstall the drivers from the CD (trying to download the latest ones from Canon's site first) and then plug in the USB cable again. Here are Microsoft's instructions on installing/uninstalling drivers for scanners.

I also found a very long thread on (different) fixes for the Canon MP Navigator, which you could try if you've no luck with any of the above - but with Jeff Widmer's fix I didn't need to!

Thursday, 20 September 2012

Firefox loads blank pages in tabs on startup? Solution

This post is on how to make Firefox load and display all webpages in all tabs automatically when you first open Firefox. Lately it just loads pages in a few tabs (3 max), but pages in all other tabs are blank with no content visible, and the status bar (visible if you use the indispensable Status4Evar add-on) shows "Stopped" at the bottom left.


Other tabs won't display anything but blank until you actually click on the tab for the page. It's very tedious to have to click for each page individually. I save webpages in tabs because I want to use them, and I can't use them if they're invisible!

The quick answer: try Firefox options, then Tab Mix Plus Options, then Session Manager options (if you use either of those extensions), and if all else fails, install the Load Tabs Progressively add-on and change its options, which is what finally worked for me.

Scroll down for full explanations and screenshots.


Many people only want saved startup tabs in Firefox to load when you click on tab, so that Firefox starts up faster. But, like this blogger and others, I want the opposite.

I have a reasonably fast computer with decent amounts of memory. As I use zillions of tabs, it's too time-consuming to have to click on one tab, wait, click on the next tab, etc. I always set my Windows computer to start all my main applications and documents automatically, so I can switch on my computer, go have breakfast or at least coffee, and when I get back to my computer it's all up and ready for me. I want browsers to do this too: I want all tabs to load and display on launching Firefox while I go do something else, and I agree that not allowing this is plain bad usability (though taking away individual users' choice of which option they want is worse).

I wasted too much time trying to troubleshoot and fiddling round with about:config till I found this page explaining that this annoyance is in fact a 'feature' which was introduced in recent versions of Firefox (13 onwards I think).

The current default setting is a pain when you have lots of tabs and have to click each one separately. The point of setting Firefox to launch with a set of tabs is because you want to use them all.

As a workaround, I'd been using 'Reload all tabs' to make all the webpages visible (rightclick on a tab heading for the menu that allows that, if you have TabMixPlus).

General setting

The suggested solution, to force all pages in all tabs load and display when Firefox opens, was to UNtick the 'Don't load tabs until selected' box and OK.

In my version of Firefox (Firefox 15) it's in the Tabs tab of Options (menu Tools, then Options, then Tabs), in others it might be in the General tab.


Like so:


However, that didn't work for me even after restarting Firefox. There are other options which may need to be set, so try those too.

If you use TabMixPlus

The same link suggested that if you use Tab Mix Plus (TMP) (also an essential extension, in my view), you need to go to TMP Options > Session > Restore and check the "Reload all tabs" checkbox.

If you use Session Manager

As I use Session Manager (which manages loads of sessions with finer control than TMP's session manager), I had no such option, so I went to Session Manager options.

Under General > Saving & Restoring, I UNticked "Restore tabs on demand" (and OK or Apply), to try to get tabs to load automatically without having to "demand" each one individually.


If all else fails

Unfortunately, none of the above worked for me - UNticking "Don't load tabs until selected" and the like did not change anything. Only 3 tabs ever loaded automatically when I started Firefox.

Therefore, I had to install an extra extension - Load Tabs Progressively. This works, but I'd recommend some tweaks.

Once you've installed it and restarted Firefox, go to Tools > Add-ons and find Load Tabs Progressively. Click its Options. Change "Maximum number of concurrent loading tabs" to 0 and "Maximum number of loaded tabs" to -1. Then OK.


Otherwise, it will load only up to a maximum number of tabs, and only a certain number at a time. If like me you have tons of tabs and just want them all to load while you do something else, you'd want it to load however many tabs you have, ideally all in one go (in my case!).

This excellent extension, as the name suggests, opens each of your saved session tabs progressively, one by one, and the settings I've recommended will get it to open all your saved session tabs no matter how many, and whether using TabMixPlus or SessionManager.